Hướng dẫn _session array cart php

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

$_SESSION — Session variables

Description

An associative array containing session variables available to the current script. See the Session functions documentation for more information on how this is used.

Notes

Note:

This is a 'superglobal', or automatic global, variable. This simply means that it is available in all scopes throughout a script. There is no need to do global $variable; to access it within functions or methods.

Tugrul ¶

7 years ago

Creating New Session
==========================
session_start();
/*session is started if you don't write this line can't use $_Session  global variable*/
$_SESSION["newsession"]=$value;
?>
Getting Session
==========================
session_start();
/*session is started if you don't write this line can't use $_Session  global variable*/
$_SESSION["newsession"]=$value;
/*session created*/
echo $_SESSION["newsession"];
/*session was getting*/
?>
Updating Session
==========================
session_start();
/*session is started if you don't write this line can't use $_Session  global variable*/
$_SESSION["newsession"]=$value;
/*it is my new session*/
$_SESSION["newsession"]=$updatedvalue;
/*session updated*/
?>
Deleting Session
==========================
session_start();
/*session is started if you don't write this line can't use $_Session  global variable*/
$_SESSION["newsession"]=$value;
unset($_SESSION["newsession"]);
/*session deleted. if you try using this you've got an error*/
?>

opajaap at opajaap dot nl ¶

9 years ago

Be carefull with $_SESSION array elements when you have the same name as a normal global.

The following example leads to unpredictable behaviour of the $wppa array elements, some are updated by normal code, some not, it is totally unpredictable what happens.

global $wppa;
$wppa = array( 'elm1' => 'value1', 'elm2' => 'value2', ....etc...);

if ( !

bohwaz ¶

14 years ago

Please note that if you have register_globals to On, global variables associated to $_SESSION variables are references, so this may lead to some weird situations.

session_start

jherry at netcourrier dot com ¶

14 years ago

You may have trouble if you use '|' in the key:

$_SESSION["foo|bar"] = "fuzzy";

This does not work for me. I think it's because the serialisation of session object is using this char so the server reset your session when it cannot read it.

To make it work I replaced '|' by '_'.

Fred ¶

9 years ago

Regarding array keys, from http://php.net/manual/en/language.types.array.php, "Strings containing valid integers will be cast to the integer type".

The manual on $_SESSION says "An associative array". So an associative array is expected literally...? It does no one any good if this bit of important info about accessing and storing session data remains buried in manual comments.

Session variables with a single number will not work, however "1a" will work, as will "a1" and even a just single letter, for example "a" will also work.

(Invalid)
1st page

session_start();
$_SESSION["1"] = "LOGGED";
?>

2nd page

session_start();
echo $_SESSION["1"];
?>

---------------------------------------------------------------

(Valid)
1st page

session_start();
$_SESSION["a"] = "LOGGED";
?>

2nd page

session_start();
echo $_SESSION["a"];
?>

---------------------------------------------------------------

(Valid)
1st page

session_start();
$_SESSION["a1"] = "LOGGED";
?>

2nd page

session_start();
echo $_SESSION["a1"];
?>

---------------------------------------------------------------

Example from PHP.net manual on Session variables

$_SESSION[1][1] = 'cake'; // fails$_SESSION['v1'][2] = 'cake'; // works
?>

Source: http://php.net/manual/en/language.types.array.php

Miller ¶

9 years ago

I wrote a little page for controlling/manipulating the session. Obviously, never use this on a production server, but I use it on my localhost to assist me in checking and changing session values on the fly.

Again, it makes use of eval() and exposes the session, so never use this on a web server.

error_reporting(E_ALL);
session_start();
if (isset($_POST['session'])) {
    $session = eval("return {$_POST['session']};");
    if (is_array($session)) {
        $_SESSION = $session;
        header("Location: {$_SERVER['PHP_SELF']}?saved");
    }
    else {
        header("Location: {$_SERVER['PHP_SELF']}?error");
    }
}$session = htmlentities(var_export($_SESSION, true));
?>


   
       
       
       
   
   
       

Session Variable Management

charlese at cvs dot com dot au ¶

13 years ago

I was having troubles with session variables working in some environments and being seriously flaky in others. I was using $_SESSION as an array. It works properly when I used $_SESSION as pointers to arrays. As an example the following code works in some environments and not others.

//Trouble if I treate $form_convert and $_SESSION['form_convert'] as unrelated items
$form_convert=array();
if (isset($_SESSION['form_convert'])){
        $form_convert=$_SESSION['form_convert'];
    }
}
?>
The following works well.
if (isset($_SESSION['form_convert'])){
    $form_convert = $_SESSION['form_convert'];
}else{
    $form_convert = array();
    $_SESSION['form_convert']=$form_convert;
}
?>